Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period			$ 6,074
Other comprehensive (loss) income before reclassification adjustments	$ (5)	$ (29)	149	$ (51)
Amounts reclassified from AOCI	(5)	7	(10)	13
Other comprehensive (loss) income attributable to UGI	(10)	(22)	139	(38)
Balance, end of period	5,214	6,210	5,214	6,210
Total
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period	(231)	(156)	(380)	(140)
Balance, end of period	(241)	(178)	(241)	(178)
Postretirement Benefit Plans
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period	14	(15)	14	(17)
Other comprehensive (loss) income before reclassification adjustments	0	0	0	0
Amounts reclassified from AOCI	0	1	0	3
Other comprehensive (loss) income attributable to UGI	0	1	0	3
Balance, end of period	14	(14)	14	(14)
Derivative Instruments
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period	35	(19)	37	(33)
Other comprehensive (loss) income before reclassification adjustments	(15)	24	(12)	34
Amounts reclassified from AOCI	(5)	6	(10)	10
Other comprehensive (loss) income attributable to UGI	(20)	30	(22)	44
Balance, end of period	15	11	15	11
Foreign Currency
AOCI Attributable to Parent, Net of Tax
Balance, beginning of period	(280)	(122)	(431)	(90)
Other comprehensive (loss) income before reclassification adjustments	10	(53)	161	(85)
Amounts reclassified from AOCI	0	0	0	0
Other comprehensive (loss) income attributable to UGI	10	(53)	161	(85)
Balance, end of period	$ (270)	$ (175)	$ (270)	$ (175)